The internal review said the officers' inexperience in dealing with "unprecedented and ferocious violence" exposed "apparent weaknesses and some errors of judgement".

Retired assistant commissioner of the Metropolitan Police, Anthony Speed, was brought in to head the review.

He said in the report: "There are questions raised about the operational effectiveness of senior officers due to an inevitable lack of field experience at major disorders."

'Highly unsatisfactory'

Mr Speed also said the operation was confused by having two operations running from the Met and City forces at the same time.

Organisational problems within the police were also revealed. The June riots left the police control room overwhelmed by information.

The Carnival Against Global Capitalism in the City of London caused an estimated £2m damage, according to the report.

Deborah Edwards, building manager of Cannonbridge House

City force commissioner Perry Nove accepted the criticisms, and said the police's handling of pitched battles inside one of London's best-known financial centres was "highly unsatisfactory".

Mr Nove said: "The City of London police accepts that a number of described generic weaknesses and some judgements exacerbated the difficulties of dealing with the very serious disorder once it had occurred.

"These are being addressed by the force."

Wide implications

The clashes were said to be the worst since the Trafalgar Square poll tax riots of 1990. They were designed to coincide with the G8 economic summit in Cologne headed by Prime Minister Tony Blair, and it was co-ordinated by the anti-car group, Reclaim the Streets.

Demonstrators broke into the London International Futures and Options Exchange (LIFFE), where security guards had to fight off rioters before police arrived. More than 40 people were injured.

The report will have implications for policing riots across England and Wales.

Other forces will study the City's response to determine whether tactics for policing riots will have to change.

City reaction

A survey of executives at leading City institutions showed they are split over the police handling of the riot.

A total of 48% said they believed the police had acted appropriately, while 40% disagreed.

European law firm Eversheds talked to 25 chief executives, managing directors and directors for the survey.

Most of the respondents - 80% - said they hoped the police would act "more firmly" if the riots were repeated.